1. Field of the Invention
The present invention relates to containers and more particularly to a disposable thermally insulated beverage container such as a paper cup.
2. Prior Art
Disposable paper cups with heat insulating capability are a desirable and widely used commodity. These types of cups are designed for hot liquid contents such as hot coffee/tea/chocolate and tend to maintain the liquid contents"" temperature by preventing undesirable heat transfer from the hot liquid contents inside the cup to the cup holder""s hand holding the cup. These cups may also be used for cold liquid contents in which case the insulated walls of the cup help maintain the cold liquid contents"" temperature by preventing undesirable heat transfer from the cup holder""s hand to the cold liquid contents.
Thermally insulated cups come in various known configurations. For example, an insulated cup is disclosed in Amberg et al (U.S. Pat. No. 3,737,093) which uses a plastic cup placed within a paper cup to create air space therebetween for thermal insulation purposes. Another insulated cup is disclosed by Iioka (U.S. Pat. No. 4,435,344) which coats a paper cup with a thermoplastic synthetic resin film which is subsequently heated to form a foamed insulating layer. Neale et al (U.S. Pat. No. 5,952,068) deals with a cup insulation layer formed from syntactic foam, a type of foam which incorporates insulating particles held in place by a binder. The insulating particles may contain an air space.
None of the known insulated cups, however, is an effective thermal insulator. Furthermore, none of the known insulated cups can be manufactured at low cost on a wide scale due to complexity of fabrication, high cost of materials, and the like.
The present invention is directed to a beverage container, comprising a side wall having an outer surface, an inner surface, and at least one air pocket formed on the inner surface by at least one strip of shrink film coupled to the inner surface in at least one pattern and adapted to pull away from the inner surface of the side wall according to the at least one pattern upon application of heat sufficient to form the at least one air pocket, the at least one air pocket thermally insulating a portion of the outer surface located directly behind the at least one air pocket.
These and other aspects of the present invention will become apparent from a review of the accompanying drawings and the following detailed description of the preferred embodiments of the present invention.